Crossbow butt stock



FIG. 1 is a back perspective view of a crossbow butt stock.

FIG. 2 is a right side view of the crossbow butt stock shown in FIG. 1.

FIG. 3 is a left side view of the crossbow butt stock shown in FIG. 1; and,

FIG. 4 is a top view of the crossbow butt stock shown in FIG. 1.

The long dash short dash short dash long dash lines and the dash dash lines shown in FIGS. 1-4 are for the purpose of illustrating an environment, and none of the broken lines shown form any part of the claimed design. 

CLAIM The ornamental design for a crossbow butt stock, as shown and described. 